BS 5839-6:2013 Fire detection and alarm systems for
buildings - Code of practice for the design, installation, commissioning and
maintenance of fire detection and fire alarm systems in domestic premises
There have been many
books published as detailed guides to BS 5839 and its many parts, some of which
extend to more than 200 pages. In this document, we are focusing on clarifying
some of the more popular issues and the questions which are commonly asked by designers,
installers and maintenance personnel.
This document is
intended as a guide to BS 5839: Pt.6: 2013. It is not a substitute for reading
the Code of practice itself. Instead, it's designed to help make the
implications and recommendations of BS 5839: Pt.6 more clearly understood, and
to offer advice on how to design, install, commission and maintain a system
that meets the requirements, with reference to the 2013 amendments.
BS 5839-6 is the key
standard for fire detection in domestic premises. It is written to assist the
non-specialist in compliance and will help make installations easier to audit.
The standard is used by enforcing authorities and contractors, and applies to
domestic premises accommodating single families, houses in multiple occupation
(HMOs) and sheltered housing (housing and common areas). It applies both to new
and existing housing.
The Document Itself
Each clause of the
document is split into 2 parts. Firstly, there is the commentary - in italics -
this sets out the reasoning behind the recommendations. The recommendations are
written in upright (roman) type, so it is quite possible to simply refer to
these alone. The intention of the commentary is to make the document easier to
use; whether it succeeds in this aim is a matter of personal perception.
BS 5839: Pt.6 - An Introduction
BS 5839: Pt.6 is not
intended for householders themselves, but to provide guidance and
recommendations for architects and other building professionals, enforcing
authorities, contractors and others responsible for implementing fire
precautions in buildings. Householders should refer to the government
guidelines.
The Code of Practice should not be quoted as if it was a specification and the standard itself warns that particular care should be taken to ensure that claims of compliance are not misleading.
It is also pointed out that compliance with a British Standard cannot automatically confer legal immunity. However, for a landlord or installer, compliance with the latest Code is obviously the best line of defence in any claim made against them.
The Code of Practice should not be quoted as if it was a specification and the standard itself warns that particular care should be taken to ensure that claims of compliance are not misleading.
It is also pointed out that compliance with a British Standard cannot automatically confer legal immunity. However, for a landlord or installer, compliance with the latest Code is obviously the best line of defence in any claim made against them.
The Scope of BS 5839: Pt. 6
This Code of Practice
covers fire alarm systems starting from a simple self-contained battery smoke
alarm right through to major systems with central panel(s) in accordance to BS
5839-pt1.
BS 5839: Pt.6 covers the following domestic building types:
Bungalows
Multi-storey houses
Individual flats
Individual maisonettes
Mobile homes
Individual sheltered accommodation as well as their common parts
Houses in multiple occupation (HMOs)
Certain NHS housing in the community
Mansions
Shared houses
Houses divided into several self-contained single-family dwelling units
Not included are hostels, caravans, boats (other than permanently moored) and communal parts of blocks or flats or maisonettes.
BS 5839: Pt.6 is primarily concerned with saving lives and reducing injuries. However, it does contain within it recommendations for helping to reduce property damage too. Good fire safety practice and adherence to the Code can give the best possible early warning of fire and so reduce the financial impact as well as human suffering.
BS 5839: Pt.6 covers the following domestic building types:
Bungalows
Multi-storey houses
Individual flats
Individual maisonettes
Mobile homes
Individual sheltered accommodation as well as their common parts
Houses in multiple occupation (HMOs)
Certain NHS housing in the community
Mansions
Shared houses
Houses divided into several self-contained single-family dwelling units
Not included are hostels, caravans, boats (other than permanently moored) and communal parts of blocks or flats or maisonettes.
BS 5839: Pt.6 is primarily concerned with saving lives and reducing injuries. However, it does contain within it recommendations for helping to reduce property damage too. Good fire safety practice and adherence to the Code can give the best possible early warning of fire and so reduce the financial impact as well as human suffering.
The Grade System
Relates to system
engineering, not level of protection.
BS 5839: Pt.6 grades fire detection systems from Grade F up to Grade A. Generally speaking, the greater the fire risk and the more demanding the application, the more comprehensive the system needs to be.
BS 5839: Pt.6 grades fire detection systems from Grade F up to Grade A. Generally speaking, the greater the fire risk and the more demanding the application, the more comprehensive the system needs to be.
· Grade F - System of one or more battery
powered smoke alarms (and heat alarms if required)
· Grade E - System of interlinked mains powered
smoke alarms (and heat alarms if required) with NO stand-by supply. The
interlink can be hardwired or radio-interlinked.
· Grade D - System incorporating one or more
interlinked mains powered smoke alarms (and heat alarms if required), each with
an integral stand-by supply. The interlink can be hardwired or
radio-interlinked.
· Grade C - System consisting of fire detectors
and alarm sounders (which may be smoke alarms) connected to a common power
supply, comprising normal mains and stand-by supply, with central control
equipment
· Grade B - Fire detection and alarm system
comprising fire detectors (other than smoke alarms), fire alarm sounders and
control and indicating equipment to either BS EN 54-2 (and power supply to BS
EN 54-4), or to Annex C of BS 5839: Pt.6
· Grade A - Fire detection system incorporating
control and indicating equipment to BS EN 54-2, and power supply to BS EN 54-4,
installed to BS 5839: Pt.1 with some very minor exceptions
As the overwhelming number of residential applications in the UK will fall into the D to F categories, this is the area on which this guide will naturally focus. If you are particularly interested in unusual grades of protection, you are invited to look further at the relevant clauses of the Code.
Of course, installers and specifiers may install a system with greater safety features than laid down in the letter of the Code. For example, rather than a Grade E system landlords might consider it prudent to install a Grade D system instead. This is especially true considering the many restrictions that apply to the use of Grade E systems.
Battery Powered Smoke Alarms - Grade F
BS 5839: Pt.6
acknowledges the advantages of the single, battery powered smoke alarm.
They are simple to install and offer protection at very low cost. Battery
powered smoke alarms conforming to BS EN 14604:2005 are recommended. Battery
powered smoke alarms are typically suitable for owner-occupied buildings
(existing buildings) with up to two storeys. Please note: if your property has
multiple levels, it is recommended to have interlinked alarms. This is to
ensure you receive the earliest possible warning of fire.
Single story tenanted
properties were allowed in the last version (2004) of this standard to be
fitted with Grade F alarms. This has now been changed to a grade D requirement.
As an aside, landlords have now been found liable in cases where tenants
themselves have disabled an alarm. For this reason, it is unlikely that
landlords will be able to trust tenants to adequately look after a smoke alarm.
The Code highlights the fact that battery powered smoke alarms are also only
suitable for owner-occupied properties if the likelihood is, that batteries
will be replaced within five days of a low battery signal.
Mains Powered Smoke Alarms without Back-up Battery - Grade E
The Code does not
recommend an application for alarms without back-up power source any longer.
Grade E systems have serious drawbacks: power cuts or the termination of supply
for whatever reason disables them totally. They can also be rendered useless by
the tripping of a protective device, or even - in some cases - by the fire
itself. Householders may also disable them at the mains all too easily if false
alarms are a problem. Some organization only offering mains powered smoke
alarms WITH back-up battery.
Mains Powered Smoke Alarms with Back-up Battery - Grade D
The problems outlined above can be overcome by
using mains powered alarms that incorporate, within each alarm, a
stand-by supply such as a primary or rechargeable battery. The alarms have to
be interconnected either through wiring or radio-interlink. The mains power
supply can come from a dedicated power supply directly from the fuse box or
from the nearest permanently powered light fitting, as long as the smoke alarm
heads can be removed without removing the base as well.
Grade D is required for new, owner-occupied buildings of up to three storeys, two storey rented properties and existing, owner-occupied buildings of more than two storeys. Very large storeys (>200m2) might require Grade B alarm system.
A question remains for landlords - can they be sure that their tenants are paying their electricity bills? Given that many tenants may have low incomes (in many local authorities, 70% or more of all tenants are on subsidised incomes), they may well experience periods of disconnection - and yet the landlord could well be liable if the alarm fails to sound because the tenant has not paid his or her bills! Unfair or not, as the law stands, it obviously makes good commercial sense to ensure that a reliable, ideally re-chargeable and sealed-in backup battery is in place.
The minimum back-up duration recommended is 72 hours, and the Code acknowledges that there could well be circumstances where a longer stand-by period is justified e.g. tenants' inability to pay their electricity bill.
Grade D is required for new, owner-occupied buildings of up to three storeys, two storey rented properties and existing, owner-occupied buildings of more than two storeys. Very large storeys (>200m2) might require Grade B alarm system.
A question remains for landlords - can they be sure that their tenants are paying their electricity bills? Given that many tenants may have low incomes (in many local authorities, 70% or more of all tenants are on subsidised incomes), they may well experience periods of disconnection - and yet the landlord could well be liable if the alarm fails to sound because the tenant has not paid his or her bills! Unfair or not, as the law stands, it obviously makes good commercial sense to ensure that a reliable, ideally re-chargeable and sealed-in backup battery is in place.
The minimum back-up duration recommended is 72 hours, and the Code acknowledges that there could well be circumstances where a longer stand-by period is justified e.g. tenants' inability to pay their electricity bill.
Fire Detectors supplied with Power from a common
Power Supply Unit - Grade A, B, C
More expensive high specification systems can
offer connection of all fire detection devices to a common power supply via low
voltage transformers, or interlinked fire and security systems. Again, a
minimum 72 hour back-up is recommended by the Code.
Levels of Protection - Categories of System
This relates to the level of protection
afforded by the system.
Within the A - F grades defined earlier, the standard identifies three different categories of protection:
Within the A - F grades defined earlier, the standard identifies three different categories of protection:
· LD1 - A system installed throughout the
dwelling, incorporating detectors in all circulation spaces that form part of
the escape routes from the dwelling, and in all rooms and areas in which fire
might start, other than toilets, bathrooms and shower rooms
· LD2 - A system incorporating detectors in all
circulation spaces that form part of the escape routes from the premises, and
in all rooms or areas that present a high risk of fire to occupants
· LD3 - A system incorporating detectors in all
circulation spaces that form part of the escape routes from the premises
It is noted that an LD3 type system is intended to protect escape routes for those not directly involved in the fire and may not save the life of anyone in the immediate vicinity of the fire.
Only by quoting Grade and Category can a meaningful and effective alarm system be specified, e.g. Grade D, Category LD2.
Grade C
Grade C, LD1 Houses providing NHS supported living in the
community. Dwellings (আবাস) of one, two or three storeys occupied by no
more than six residents.
• Control and indication panel with battery
back-up for use in sheltered housing
• Intruder alarm system may also support 12
Volt smoke and heat alarms
• Social alarm system may also support 12 Volt
smoke and heat alarms
• Carbon monoxide detectors can be added to
the system.
• System is designed in accordance with the
recommendations of BS 5839-1 Sections 1-4 with BS 5839-6 clauses 13,14,18,15.20
and 21 replacing the similar clauses of BS 5839-1
• Fire detectors in all the communal areas
(the fire-risk assessment may define that a heat detector and sounder should be
located inside each flat, within 1 metre of the main door and directly
connected to the communal system)
• Manual call points may be sited on the fire
exit route of the common parts, at all storey exits and to the open air
• May be interconnected using radio links
• May be wired in standard non-fire resistant
cable
• Requires a dedicated mains supply
• The sound pressure level of the alarm signal
measured at the doorway of each bedroom with the door open should be at least
85dB(A), unless a fire risk assessment determines that the sound pressure level
should be higher 75dB(A) at the bed head
• Where the design of the flat has no door
separating the kitchen from the circulation or living space, a smoke detector
may be used, subject to a fire risk assessment establishing that the kitchen
extract system will be able to prevent false alarms being caused by food
preparation
• Intruder and social alarm systems may be
considered for connecting to an alarm receiving centre (ARC)
Grade C, LD2 Sheltered housing (individual dwelling units
only) - New or materially altered dwellings or existing dwellings where the
structural fire precautions are of a lower standard.
• Control and indication panel with battery
back-up for use in sheltered housing.
• Intruder alarm system may also support
12Volt smoke and heat alarms
• Social alarm system may also support 12Volt
smoke and heat alarms
• Carbon monoxide detectors can be added to
the system
• Optical alarms in hallways and landings,
heat detectors in the kitchen and lounge
• May be interconnected using radio links
• May be wired in standard non-fire-resistant
cable
• Requires a dedicated mains supply
• The sound pressure level of the alarm signal
measured at the doorway of each bedroom with the door open should be at least
85dB(A), unless a fire risk assessment determines that the sound pressure level
should be higher. 75dB(A) at the bed head
• Where the design of the flat has no door
separating the kitchen from the circulation or living space a smoke detector
may be used, subject to a fire risk assessment establishing that the kitchen
extract system will be able to prevent false alarms being caused by food
preparation
• Intruder and social alarm systems may be
considered for connecting to an alarm receiving centre (ARC)
Grade C, LD3 Sheltered housing (Individual dwelling units
only) - Existing dwellings only.
• Control and indication panel with battery
back-up for use in sheltered housing
• Intruder alarm system may also support
12Volt smoke and heat alarms
• Social alarm system may also support 12Volt
smoke and heat alarms
• Carbon monoxide detectors can be added to
the system
• Optical alarms in hallways and landings
• May be interconnected using radio links
• May be wired in standard non-fire-resistant
cable
• Requires a dedicated mains supply
• The independent system in each unit should
derive its mains supply from a dedicated supply
• The sound pressure level of the alarm signal
measured at the doorway of each bedroom with the door open should be at least
85dB(A), unless a fire risk assessment determines that the sound pressure level
should be higher. 75dB(A) at the bed head
• Where the design of the flat has no door
separating the kitchen from the circulation or living space a smoke detector
may be used, subject to a fire risk assessment establishing that the kitchen
extract system will be able to prevent false alarms being caused by food
preparation
• Intruder and social alarm systems may be
considered for connecting to an alarm receiving centre (ARC)
Grade C, PD2 Property protection only where specified. These
consist of - Single or two-storey dwellings. Other dwellings as PD1.
• Control and indication panel with battery
back-up for use in sheltered housing.
• System is used solely for the protection of
the property
• Fire detectors in a PD2 system would be
installed in specified areas of the building.
• May be interconnected using radio links
• May be wired in standard cable
• System should have its own dedicated mains
supply
• The system will generally have a minimum of
two sounders, one of which will be on the external face of the building
adjacent to the control and indication panel
• Will be connected to an alarm receiving
centre (ARC)
Grade B
Grade B, LD2 New or materially altered dwellings or
existing dwellings where structural fire precautions are of a lower level.
Single-family dwellings and shared houses with no floor greater than 200sq
metres in area. These consist of four or more storey houses. New or materially
altered dwellings or existing dwellings where structural fire precautions are of
a lower level. Single-family dwellings and shared houses with one or more floor
greater than 200sq metres in area. These consist of maisonettes or two-storey
houses.
• With the exception of the indicator panel
the system should conform to BS 5839-1, and may accommodate fire detectors
other than smoke and heat alarms
• Basic indication panel with battery back-up
(conforming with EN 54-2, EN54-4 or annex C of BS 5839-6); this is not a
standard panel; Consider using standard conventional fire alarm panel as used
for Grade A system. This may be more competitive
• Optical alarms in hallways and landings,
heat detectors in the kitchen and lounge. (Additional detectors may be needed
subject to the fire risk assessment)
• May be interconnected using radio links
• Should be wired in standard fire-resistant
cable, particularly for the mains supply
• System should have its own dedicated mains
supply
• The sound pressure level of the alarm signal
measured at the doorway of each bedroom with the door open should be at least
85dB(A), unless a fire risk assessment determines that the sound pressure level
should be higher. 75dB(A) at the bed head
• Where the design of the flat has no door
separating the kitchen from the circulation or living space a smoke detector
may be used, subject to a fire risk assessment establishing that the kitchen
extract system will be able to prevent false alarms being caused by food
preparation
Grade A
Grade A, LD1 HMOs, Single-family dwellings and shared
houses with one or more floors greater than 200sq metres. (Note: FSO guidance
for sleeping risks allows HMOs of more than two storeys (more than one storey
above ground), flats and conversions (including holiday flats) that have not
been constructed to building regulation standards may have an LD2 category of
system installed.)
These dwellings consist of - Three or more
storey houses.
Houses of Multiple Occupation - Communal areas
only.
• Conventional or addressable control and
indication panel with battery back-up (conforming with EN 54-2 and EN 54-4) covering
the communal areas
• Where rented individual flats are included
these systems should be self-contained and installed to Grade D LD2 standard
• System is designed in accordance with the
recommendations of BS 5839-1 sections 1-4, with BS 5839-6 clauses
13,14,18,15.20 and 21 replacing the similar clauses of BS 5839-1
• Fire detectors in all the communal areas
(the fire risk assessment may define that a heat detector and sounder should be
located inside each flat, within 1 metre of the main door and directly
connected to the communal system)
• Manual call points should be sited on the
fire exit route of the common parts at all storey exits and to the open air
• May be interconnected using radio links
• The communal system should be wired in
standard or enhanced fire-resistant cable; this includes the mains supply
• The communal system should have its own
dedicated mains supply
• The independent system in each flat may
derive its mains supply from a dedicated supply or a regularly used local
lighting circuit
• Each system in the flats may be wired in
non-fire-resistant cable
• If a conventional control and indicating
panel is used, a remote indicator should be located outside the flat or the
flat number or the location should be indicated in text on an addressable
control and indication panel
• The sound pressure level of the alarm signal
measured at the doorway of each bedroom with the door open should be at least
85dB(A), unless a fire risk assessment determines that the sound pressure level
should be higher. 75dB(A) at the bed head
• Where the design of the flat has no door
separating the kitchen from the circulation or living space a smoke detector
may be used, subject to a fire risk assessment establishing that the kitchen
extract system will be able to prevent false alarms being caused by food
preparation
• Depending on the fire risk assessment the
communal system may be connected to an alarm receiving centre (ARC)
Grade A, PD1 as LD1 above. PD2 Property protection of
dwellings only where specified (no sleeping risk), see recommendations below.
This is usually for insurance purposes.
• Conventional or addressable control and
indication panel with battery back-up (conforming with EN 54-2 and EN54-4)
• System generally specified by insurers and
is solely for the protection of the property
• System is designed in accordance with the
recommendations of BS 5839-1 sections 1-4 with BS 5839-6 clauses 13,14,18,15.20
and 21 replacing those of BS 5839-1
• Fire detectors in a PD2 system would be
installed in defined areas of the building. On the rare occasion that a PD1
system is specified the detectors would be located throughout the building
except toilets, bath and shower rooms
• May be interconnected using radio links
• Should be wired in standard or enhanced
fire-resistant cable; this includes the mains supply
• System should have its own dedicated mains
supply
• The system will generally have a minimum of
two sounders, one of which will be on the external face of the building
adjacent to the control and indication panel
• Will be connected to an alarm receiving
centre (ARC)
You can buy the full BS
5839-6:2013 standard online.
History of BS 5839-part 6
When first introduced in 1995, the BS 5839:
Pt.6 Code of Practice became the most important set of recommendations ever
made on fire safety in the home.
It had an immediate impact on architects, system designers, installers and landlords in the private or public sector, all of whom were required to familiarise themselves with these important recommendations. Landlords in particular needed to abide by these recommendations, as legal liability with regard to 'duty of care' would undoubtedly become a serious issue should a fire occur in an inadequately protected property.
In short, BS 5839: Pt.6 became the essential guide to providing adequate fire protection in all dwelling types.
In September 2004, the Code of Practice was extensively revised and updated by the publication of BS 5839: Pt.6: 2004 which superseded BS 5839: Pt.6: 1995, which is now withdrawn. The changes therein are important and need to be fully understood and appreciated by all those with responsibility for fire safety in domestic dwellings.
An updated standard came out in 2013 and included for the first time common areas in sheltered housing. Carbon monoxide detectors were also permitted as fire alarm sensors and the requirement for rented accommodations were tightened.
It had an immediate impact on architects, system designers, installers and landlords in the private or public sector, all of whom were required to familiarise themselves with these important recommendations. Landlords in particular needed to abide by these recommendations, as legal liability with regard to 'duty of care' would undoubtedly become a serious issue should a fire occur in an inadequately protected property.
In short, BS 5839: Pt.6 became the essential guide to providing adequate fire protection in all dwelling types.
In September 2004, the Code of Practice was extensively revised and updated by the publication of BS 5839: Pt.6: 2004 which superseded BS 5839: Pt.6: 1995, which is now withdrawn. The changes therein are important and need to be fully understood and appreciated by all those with responsibility for fire safety in domestic dwellings.
An updated standard came out in 2013 and included for the first time common areas in sheltered housing. Carbon monoxide detectors were also permitted as fire alarm sensors and the requirement for rented accommodations were tightened.
Types of Detector
Optical Alarms - where should they be used?
Optical sensors are more responsive to
smouldering fires producing large particle smoke typical of fires involving
furniture and bedding. They are more immune to invisible smoke produced by
‘burning the toast’ and similar cooking fumes. This makes them ideal for locating
in hallways close to kitchens, where false alarms from ionisation alarms may be
a particular problem. BS 5839: Pt.6: 2013 recommends the use of optical alarms
in circulation spaces of a dwelling, such as hallways and landings. Optical
alarms are prone to false alarm if exposed to steam and should not be located
too close to poorly ventilated bathrooms or shower rooms.
1. A light beam is pulsed in the sensor
chamber every 10 seconds to ‘look’ for smoke. Any smoke present has to be
visible to the naked eye so that the receptor can ‘see’ it. If no smoke is
detected, the alarm will remain in a standby state.
2. When large particle smoke is detected, the
light beam will be scattered onto the light receptor.
3. This will then send an electrical signal to
the Integrated Circuit (IC).
4. If the IC receives two consecutive signals,
the alarm will sound.
Heat Alarms - where should they be used?
Heat alarms are less likely to cause false
alarm problems, as they are not responsive to any type of smoke or fumes. They
only detect heat. This type of detector will provide a slower response than
smoke alarms. All of the alarm units should be inter connected. BS 5839-6: 2013
recommends that heat alarms should be used in kitchens. It goes on to suggest
that they may also have a role to play in the main living room but they should
not be installed in circulation spaces or areas where fast response to fire is
required.
1. A thermistor (a heat sensitive resistor) is
sited in the sensor chamber of the alarm.
2. When heat is detected the thermistor will
send an electrical signal to the Integrated Circuit (IC).
3. If the IC receives two consecutive signals
the alarm will sound.
Ionisation Alarms - where should they be used?
Ionisation sensors are particularly sensitive
to the almost invisible smoke produced by fast flaming fires. This makes them
more liable to false alarm due to cooking fumes if sited in a hallway close to
a kitchen. Ionisation alarms are less vulnerable to false alarms caused by dense
tobacco smoke, excessive dust or insect ingress. BS 5839: Pt.6: 2004 recommends
that ionisation alarms should not be used in hallways and landings, where there
is a risk of false alarms caused by cooking fumes.
1. An Ionisation detector is designed to
provide an early warning of a fast burning fire (not smoke). The ionisation
device has two electrodes within an ionisation chamber, between which a
measured resistance of negative ions flow. This circuit is connected to a
potential divider in the Integrated Circuit (IC), which remains in a constant
closed standby state.
2. In consuming fuel, fire creates combustion
gas, which gives off positive ions. When these positive ions enter the
ionisation chamber, the positive ions join themselves to the negative ions
flowing from the radioactive source and between the electrodes, changing the
resistance of the flow.
3. The resistance is applied to the potential
divider in the IC and allows current to flow.
4. If the IC receives a continuous signal, the
alarm will sound.
Location and
Positioning of Fire Detectors
When siting detectors in a hallway, no smoke
detector should be more than 7.5 metres horizontally from any point in the
hallway. In rooms, again no smoke detector should be sited more than 7.5 metres
from any point of the room. For heat detection, this distance should be reduced
to 5.3 metres. No smoke alarms should be installed less than 300mm from any
wall or beam. In a room or hallway, 10m x 10m or 50 m2 where ceiling mounting
is impractical, detectors may be mounted on the wall between 150mm and 300mm
from the ceiling.
Do
not install smoke or heat alarms in bathrooms, shower rooms or toilets, except
where the fire risk assessment identifies a specific need e.g. the presence of
a boiler.
Note:
For roofs with a pitch deeper than 600mm, smoke detectors should be within the top
600mm and heat detectors within 150mm. Allow increased coverage over 7.5m for smoke
detectors and 5.3m for heat detector spacing’s due to the angle of the roof
which will then be applicable at 1% for each degree of slope up to a maximum of
25%.
Typical
three floor house (HMO) with flats and apartment units on each floor, installed
to Grade A (BS 5839-1) Category LD3 in the units and L3 in the common areas.
The diagram below shows a house converted into
flats (HMO). In this typical system each flat has its own dedicated system (see
the symbol above). There is also a communal system, which covers the escape
routes and rooms opening onto the escape routes.
Should a false alarm occur in any of the
flats, it will not affect any of the others. Some specifiers require that if a
flat is unoccupied and a fire occurs, a heat alarm inside the flat (connected
to the escape route system, but not the system in the apartments) will operate
the communal system in the escape routes plus the heat alarm adjacent to the main
entrance door in each of the other flats, thus providing a vital early warning.
Use of manual call
points
Manual call points should be provided in very large
single-family dwellings or student accommodation. This will also generally
apply to houses with four storeys or more, multi-storey mansions, country
houses and houses of multiple occupation (HMO).
It would be appropriate to consider the use of
manual call points in all Grade A systems.
Alarm Systems for the
Deaf and Hearing Impaired
BS 5839-6 makes recommendations for people
with hearing difficulties who require a different approach to fire protection,
as a conventional alarm sounder will probably not be sufficient for their
needs.
Those with hearing difficulties will need to
use strobe units and a vibrating pad located under the pillow. This equipment
can be connected to the Grade A, B, C or D systems either by hard wire or
wireless (radio) installation.
Audibility of Fire
Alarm Warning Devices
A fire detection and alarm system only
provides satisfactory protection if it is capable of rousing at least the
principal occupants of the dwelling. It is known that greater sound levels are
required to rouse children, older people with poor hearing and impaired persons
(alcohol and drugs). International tests have shown that from these groups
120dB(A) has failed to wake some of those tested.
As we have identified earlier, BS 5839-6 recommends
85dB(A) at the doorway of each bedroom (with the door open). A closed door can reduce
this by as much as 30dB(A). The document does, however, go on to say that
higher levels may by required to rouse certain groups of people. The
international research regarding sound pressure levels suggests that 75dB(A) at
the bed head is a minimum sound pressure level and that even this may not be
enough. Whilst the text of BS 5839-6 identifies this sound pressure level it makes
no specific further recommendation, stating only that higher sound pressure
levels should be determined as part of a fire risk assessment.
Great care should be taken when installing systems
in buildings such as single-family dwellings, where there is likely to be no
fire risk assessment available. Such an assessment should be carried out in
close consultation with the occupants, building control or the person
responsible for the dwelling. It is not the installer’s responsibility to
specify sound pressure levels outside those recommended by BS 5839-6. However,
you should be able to draw the attention of the interested persons to the
existence of this particular risk.
Zoning of Systems
Zoning is generally restricted to Grades A, B,
and C systems. These are systems which will have a control and indicating
panel. In most dwellings the zonal configuration would be on a floor-by-floor
basis. However, in larger HMOs there will probably be a complex zone configuration
and even a cause and effect matrix. In these buildings addressable systems would
be appropriate.
• For Grade A systems in HMOs there should be a means of
identifying the dwelling unit where the fire signal originated. This could be
addressable text or a remote indicator outside each flat. The panel should be compliant
with EN 54.
• For Grade B systems each floor is generally treated as a zone.
This does not need to be an EN 54 panel, although it may be cheaper to use a
standard small EN 54 panel than to build one with the lesser facilities
allowable in this Grade of system.
• Grade C systems do not normally need to be divided into zones
for fire.
Wiring &
Installation
The wiring of fire alarm and detection systems
is carried out in accordance with BS5839 Parts 1 and 6, which reference
compliance with BS 7671 Requirements for Electrical Installations (IEE Wiring
Regulations Seventeenth Edition).
• Grade A systems recommend the use of
fire-resistant cables
• Grade B systems recommend the use of
fire-resistant cables
• Grade C systems recommend that cable should
be suitable for the current and voltage of the circuits concerned
• Grades D and E cables used may comprise of
any cable suitable for domestic wiring
• Grade F cables used to interconnect the
battery powered smoke alarms may be any type of cable suitable for the current
and voltage concerned
Maintenance &
Servicing
System maintenance is critical in the
performance of the system over its lifetime. The system users should be
encouraged to have their systems maintained at the appropriate intervals by a
competent person.
• To comply with BS 5839-6 recommendation, BS
5839-1 based Grade A systems should be inspected at periods not exceeding six
months
• Grades B and C systems should be inspected
at periods not exceeding six months
• Grades D, E and F systems should be tested
and cleaned in accordance with the manufacturer’s instructions
• Weekly sound checks by the user
• System servicing should be carried out by an
organisation that can provide 24-hour service availability and by competent service
and maintenance personnel.
System Certification
Upon completion of a system, the appropriate
certificates should be completed and signed by a competent person.
1) Grade A system (BS 5839-1/6)
a) BS 5839-6 Design certificate
b) BS 5839-6 Installation certificate (plus a
BS 7671 Electrical Installation Certificate to support the registration for a
Part P Certificate)
c) BS 5839-6 Commissioning certificate
d) BS 5839-6 Acceptance certificate
2) Grades B, C, D, E and F systems (BS 5839-6)
a) BS 5839-6 single certificate should be
completed for all the above types of system (and should include a BS 7671
Electrical Installation Certificate or a Minor Electrical Installation Works
Certificate to support the reporting procedure for a Part P Certificate)
Documentation
The installer is required to provide
documented information to the interested parties relating to the maintenance
and operation of the system which has been installed. This, in the case of
small systems D, E and F, may be as little as the manufacturer’s instructions.
BS EN 54:
fire detection & alarm systems
BS EN 54-1:2011 - Introduction
BS EN 54-2:1997+A1:2006 - Control
and Indicating Equipment
BS EN 54-3:2001 - Fire alarm devices:
sounders
BS EN 54-4:1998 - Power supply equipment
BS EN 54-5:2001 - Heat detectors: Point
detectors
BS EN 54-7:2001 - Smoke detectors: point
detectors using scattered light, transmitted light or ionization
BS EN 54-10:2002 - Flame detectors: point
detectors
BS EN 54-11:2001 - Manual call points
BS EN 54-12:2002 - Smoke detectors: line detectors
using an optical light beam
BS EN 54-13:2005 - Compatibility assessment of
system components
BS EN 54-16:2008 - Voice alarm control and
indicating equipment
BS EN 54-17:2005 - Short-circuit isolators
BS EN 54-18:2005 - Input/output devices
BS EN 54-20:2006 - Aspirating smoke detectors
BS EN 54-21:2006 - Alarm transmission and
fault warning routing equipment
BS EN 54-22:2015 - Resettable line-type heat
detectors
BS EN 54-23:2010 - Fire alarm devices. Visual
alarm devices
BS EN 54-24:2008 - Components of voice alarm
systems: Loudspeakers
BS EN 54-25:2008 - Components using radio
links
BS EN 54-26:2015 - Point fire detectors using
carbon monoxide sensors
BS EN 54-29:2015 - Multi-sensor fire detectors – Point detectors using a
combination of smoke and heat sensors
BS EN 54-30:2015 - Multi-sensor fire detectors
– Point detectors using a combination of carbon monoxide and optionally heat
detectors
BS EN 54-31:2014 - Multi-sensor fire detectors
– Point detectors using a combination of smoke, carbon monoxide and optionally
heat sensors